Approach:
Previous research showed that roots of glyphosate-treated plants have elevated populations of fungal pathogens (Fusarium, Pythium, and Rhizoctonia) which can infect subsequently planted crop plants. Reduced corn yields are sometimes observed following glyphosate-killed cover crops. This research would determine the levels of these pathogens in corn roots where corn is planted after rye cover crop killed with glyphosate or corn without a preceeding cover crop. This comparison would be carried out in field soil or field soil inoculated with these pathogens. The effect of fungicide seed treatments on disease will also be examined. Experiments would be conducted in growth chambers and in field plots.